Conventional LC type optical connector plug has an attaching and detaching structure for coupling and releasing an adaptor or a receptacle, which are coupling counterpart members to be fitted and coupled with the plug. As shown in FIGS. 14A and 14B, an optical connector plug 15 is provided with a latching portion 17 curved and warped up from a front housing 16. A rear housing 18 is provide with a releasing bar 19 having a distal end 19a which extends opposite the latching portion 17 and which covers over and engages with a distal end 17b of the latching portion 17.
An engaging projection 17a protrudes on each of two side wall faces of the latching portion 17, configured to engage with a recess of a coupling counterpart member 21 such as an adaptor, and to prevent extraction. The releasing bar 19 extends upward from an upper face of the rear housing 18, and is forced to return to an upper original position by elastic force of the latching portion 17.
In order to releasing the optical connector plug 15 in a coupling state with a coupling counterpart member 21 as shown in FIG. 15A, it is required to press down the releasing bar 19 with fingers to release engagement of the engaging projection 17a of the latching portion 17, and then to pull the optical connector plug 15 toward a direction apart from the coupling counterpart member 21 while keeping a state where the latching portion 17 is pressed down, as shown in FIG. 15B. A duplex connector plug described in PTL 1 is known as an example of the attaching and detaching structure of the optical connector plug 15 in this manner.